On Sun, Nov 23, 2014 at 11:18:00PM -0800, Jaegeuk Kim wrote: > On Mon, Nov 24, 2014 at 03:19:43PM +0900, Changman Lee wrote: > > On Sun, Nov 23, 2014 at 09:42:12PM -0800, Jaegeuk Kim wrote: > > > On Thu, Nov 20, 2014 at 01:38:51PM +0900, Changman Lee wrote: > > > > On Fri, Nov 14, 2014 at 02:53:02PM +0900, Changman Lee wrote: > > > > > On Thu, Nov 13, 2014 at 05:27:51PM -0800, Jaegeuk Kim wrote: > > > > > > Hi Changman, > > > > > > > > > > > > On Thu, Nov 13, 2014 at 02:34:50PM +0900, Changman Lee wrote: > > > > > > > To use cleancache, fs must explicitly enable cleancache by calling > > > > > > > cleancache_init_fs. > > > > > > > > > > > > Good catch! > > > > > > > > > > > > Prior to merge this patch, can you share any testing results or performance > > > > > > numbers? > > > > > > > > > > > Not yet, I'll try to get numbers. > > > > > > > > > > > > > Hi, > > > > > > > > This is the result of kernel compile on xen-4.4 enabled tmem > > > > : cleancache and frontswap. > > > > I'm afraid that there is little difference by cleancache. > > > > The cleancache shows a few cache hits but the effect through it doesn't > > > > show. I don't know best benchmark to testify it yet. > > > > Finally, I couldn't discover any bug during test. > > > > > > > > [before patch] > > > > 1 2 3 > > > > Elapsed time 25:00.67 25:07.09 25:00.38 > > > > Major fault 31100 31410 31333 > > > > Minor fault 276869398 276869318 276871144 > > > > > > > > [after patch] > > > > 1 2 3 > > > > Elapsed time 25:12.34 25:13.29 25:11.99 > > > > Major fault 31559 32069 31801 > > > > Minor fault 276870283 276868046 276869251 > > > > > > > > [cleancache] - diff between start and end > > > > 1 2 3 > > > > failed_gets 1277980 1296355 1300368 > > > > invalidates 2588227 2651722 2655285 > > > > puts 1289970 1323685 1320623 > > > > *succ_gets* 111111 121299 114310 > > > > > > Hi Changman, > > > > > > So, what is your suggestion? > > > IMO, we first need to find a way exploiting cleancache over f2fs, so that > > > we can introduce some guide for users. > > > Until then, how about keeping this patch for a while? > > > > > > > The performance of cleancache depends on workload but ext4 and btrfs > > support it already. So how about allowing to enable cleancache on f2fs? > > If backend of cleancache doesn't exists, there is no effect for f2fs. > > I think negative effectness of cleancache is little. > > Anyway, a final decision lies in your hand. > > I'm not sure, but it seems that nobody uses the cleancache. > https://www.google.co.kr/trends/explore#q=cleancache > > And, as you've shown even worse performance under a simple workload, I don't > understand why you want to add this. > > Let me know, if I'm missing any rationale. > Okay, let's keep it until before finding a way exploiting it well. I thought to estimate firefox's startup time. To do it, however, I needed to install ubuntu on f2fs. It takes long time to set up test environment. So I gave up. :( I have no rationale now. > > > > Thanks > > > > > Thanks, > > > > > > > > > > > Thanks, > > > > Changman > > > > > > > > > > What condition will be the best way to exploit f2fs and cleancache? > > > > > > > > > > > Not clear. > > > > > I think we can make a cleancache client for f2fs so that can compenstate > > > > > a penalty of node pages which are read mostly. > > > > > > > > > > > Can we confirm that f2fs satisfies most of requirements described by > > > > > > cleancache.txt below? > > > > > > > > > > Good point. > > > > > At a quick glance, F2FS seems to satisfy most of requirements. > > > > > Through a experimental, I'll try to check side effect. > > > > > > > > > > > > > > > > > Some points for a filesystem to consider: > > > > > > > > > > > > - The FS should be block-device-based (e.g. a ram-based FS such > > > > > > as tmpfs should not enable cleancache) > > > > > > - To ensure coherency/correctness, the FS must ensure that all > > > > > > file removal or truncation operations either go through VFS or > > > > > > add hooks to do the equivalent cleancache "invalidate" operations > > > > > > - To ensure coherency/correctness, either inode numbers must > > > > > > be unique across the lifetime of the on-disk file OR the > > > > > > FS must provide an "encode_fh" function. > > > > > > - The FS must call the VFS superblock alloc and deactivate routines > > > > > > or add hooks to do the equivalent cleancache calls done there. > > > > > > - To maximize performance, all pages fetched from the FS should > > > > > > go through the do_mpag_readpage routine or the FS should add > > > > > > hooks to do the equivalent (cf. btrfs) > > > > > > - Currently, the FS blocksize must be the same as PAGESIZE. This > > > > > > is not an architectural restriction, but no backends currently > > > > > > support anything different. > > > > > > - A clustered FS should invoke the "shared_init_fs" cleancache > > > > > > hook to get best performance for some backends. > > > > > > > > > > > > Thanks, > > > > > > > > > > > > > > > > > > > > Signed-off-by: Changman Lee <cm224.lee@xxxxxxxxxxx> > > > > > > > --- > > > > > > > fs/f2fs/super.c | 3 +++ > > > > > > > 1 file changed, 3 insertions(+) > > > > > > > > > > > > > > diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c > > > > > > > index 512ffd8..2ebb960 100644 > > > > > > > --- a/fs/f2fs/super.c > > > > > > > +++ b/fs/f2fs/super.c > > > > > > > @@ -24,6 +24,7 @@ > > > > > > > #include <linux/blkdev.h> > > > > > > > #include <linux/f2fs_fs.h> > > > > > > > #include <linux/sysfs.h> > > > > > > > +#include <linux/cleancache.h> > > > > > > > > > > > > > > #include "f2fs.h" > > > > > > > #include "node.h" > > > > > > > @@ -1144,6 +1145,8 @@ try_onemore: > > > > > > > if (err) > > > > > > > goto free_kobj; > > > > > > > } > > > > > > > + > > > > > > > + cleancache_init_fs(sb); > > > > > > > return 0; > > > > > > > > > > > > > > free_kobj: > > > > > > > -- > > > > > > > 1.9.1 > > > > > > > > > > > > > > > > > > > > > ------------------------------------------------------------------------------ > > > > > > > Comprehensive Server Monitoring with Site24x7. > > > > > > > Monitor 10 servers for $9/Month. > > > > > > > Get alerted through email, SMS, voice calls or mobile push notifications. > > > > > > > Take corrective actions from your mobile device. > > > > > > > http://pubads.g.doubleclick.net/gampad/clk?id=154624111&iu=/4140/ostg.clktrk > > > > > > > _______________________________________________ > > > > > > > Linux-f2fs-devel mailing list > > > > > > > Linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx > > > > > > > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel > > > > > > > > > > ------------------------------------------------------------------------------ > > > > > Comprehensive Server Monitoring with Site24x7. > > > > > Monitor 10 servers for $9/Month. > > > > > Get alerted through email, SMS, voice calls or mobile push notifications. > > > > > Take corrective actions from your mobile device. > > > > > http://pubads.g.doubleclick.net/gampad/clk?id=154624111&iu=/4140/ostg.clktrk > > > > > _______________________________________________ > > > > > Linux-f2fs-devel mailing list > > > > > Linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx > > > > > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
